Many electrical devices require one or more batteries to operate. One such electrical device is a night vision device which allows military and law enforcement personnel to conduct operation in low light or at night. Another example of a device containing a battery is a digital camera.
An example of a conventional device including a single battery housing is shown in FIGS. 1 and 2. The battery housing includes a 1.5 volt AA battery which provides sufficient power to operate an image intensifier of a night vision goggle system. FIG. 1 shows a single battery housing assembly 300, which includes an on/off switch 216, electronics assembly 206, and a battery cap assembly 310. Fastener posts 204A, 204B, 204C and 204D enable the single battery housing assembly to be connected to a monocular housing assembly. FIG. 1 also shows a lanyard 205 coupled to a lanyard retention post 319. Lanyard 205 has loops 209 and 210 at respective ends. Loop 209 may be placed under post 319. A portion of the lanyard between loops 209 and 210 may be placed in groove 208 of post 204D. When the monocular housing assembly (not shown) is connected to single battery housing assembly 300 with fasteners in posts 204A, 204B, 204C and 204D, lanyard 205 may be clamped into groove 208. When battery cap assembly 310 is removed, lanyard 205 and battery cap assembly 310 may not be misplaced because lanyard 205 is captured by groove 208.
FIG. 2 shows an assembled battery sleeve assembly 600. When the components of the battery sleeve assembly are assembled, positive connector 631 of a leaf spring (not shown) protrudes from spring insulator 640 through hole 645 and negative connector 658 projects from the outer surface of battery sleeve 610. Negative connector 658 and positive connector 631 make appropriate connections with a flex circuit of the monocular night vision device and with the negative and positive terminals of a battery inside the battery assembly. Positive connector 631 and negative connector 658 are aligned parallel to the longitudinal axis of battery assembly housing 600.
Battery sleeve 610 has an open end 650. Battery sleeve 610 may be a single conducting cylinder that is machined into multiple segments. Segment 652, which may comprise about 10% of the total length of battery sleeve 610, is externally threaded and forms open end 650. The external threads of segment 652 interface with internal threads on battery cap assembly 310. Immediately adjacent to segment 652 is shown o-ring groove 655. When battery cap assembly 310 threads onto the external threads of segment 652, battery cap assembly 310 extends over segment 652 and interfaces with o-ring groove 655 to form an environmental seal which prevents the battery housing assembly from being impacted by any type of moisture including salt water, sand and dust.
Referring next to FIGS. 3A, 3B and 3C, once the battery sleeve assembly 600 is assembled, it is inserted into an injection mold tool which creates battery housing 700 around the assembly by an overmolding process. During the overmolding process, a liquid high temperature, conductive plastic glows into the injection mold tooling, wraps around the battery sleeve assembly, and fills all voids in the injection mold tooling cavity.
At the conclusion of the mold-around process, battery sleeve assembly housing 600 is inside battery housing 700 and forms the battery housing/sleeve assembly. At the completion of the mold-around process, end 650 and segment 652 of battery sleeve assembly 600 protrude from opening 706 (see FIG. 3C) in battery housing 700, and end portion 640 is inside battery housing 700 and cannot be seen outside the battery housing. The inside of battery housing 700 may have two breakthroughs 702, 704, so that positive connector 631 may protrude from breakthrough 704 and negative connector 658 may protrude from breakthrough 702. The protruding connectors are shown in FIG. 3A. After the overmolding process has been completed, a separate adhesive seal is applied around positive connector 631 and/or around negative connector 658. The adhesive seal creates an environmental seal between spring insulator 640 and positive connector 631.
A disadvantage of the battery sleeve shown in FIG. 2 is that battery sleeve assembly 600 is a machined part that includes an integral ground post, or negative terminal 658, that requires additional machining time. It also includes an end cap portion 640 that must be pressed onto battery sleeve 610. Once pressed onto battery sleeve 610, the whole sleeve assembly 600 is overmolded in battery housing 700. In addition, the inside of end cap 640 includes a positive contact spring (not shown) and an insulating washer (not shown), which are also overmolded in the same process.
The machined end cap 640 and the machined long battery sleeve 610 with milled contact post 658 require a larger rod of metal and greater machining time. This results in additional costs. The overmolding process requires hand loading of the battery sleeve assembly 600 into the mold and requires costly inspection during the molding process.
Another disadvantage is that the end cap portion 640, which conventionally is made of aluminum, requires expensive complicated multiple pieces and a contact cap for forming the positive terminal. Furthermore, the negative terminal 658, because it is an integral part of sleeve 610, requires a difficult soldering process to a wire (not shown). The integral negative terminal 658 acts as a large heat sink for sleeve 610, which pulls down the temperature of the solder iron.
As will be explained the present invention overcomes the aforementioned disadvantages by providing a battery housing that has a reduced number of parts, does not require overmolding, does not require an end cap made of metal, and does not require an integral negative battery terminal.